Can't sleep

It's so darned frustrating when my baby sleeps 5-7 hours in a row and I consistently wake up at least an hour before her... and then can't get back to sleep till after I feed her! I hope and pray I can start sleeping at the exact times when she sleeps. It seems like in the beginning I slept more readily, maybe because I was so sleep deprived. Now it turns into a mind game every time I lie down at night (or morning) as to how quickly I'll fall asleep, and how soon she'll need me. I CRAVE solid sleep like air or food.